I think Bamboo is perfectly appropriate in a Mediterranean garden. However it is seriously messy. I wouldn't plant it near a pool. It's also quite thirsty.

You want like a hedge or screen? How tall does it need to be? How wide can it be?

I don't really want a hedge anymore...just a few huge shrubs or smaller trees placed in some key areas.

I have 3 areas to plant things....each have a space to fill measuring 15-20 feet tall by 15 feet wide or so.

Oneof the areas in in full sun, the other gets about 6 hours of sun, and the third is partially shaded.

I thought the ceanothus for the full sun section....not sure of what other large shrubs or small trees would work? I would love a smoke bush, but they get leggy....the foliage would be nice though.

I am so confused LOL We just moved to this area about 7 months ago, and were from a zone 5 climate before and despite me tryig to read everything I can on this climate I am not finding too much information on trees.

Was the removed hedge used as a screen from the neighbors? Are you looking for another screen, if so how high would it need to be? Is the ivy in your yard or the neighbors? If you can not remove the ivy, it will continue to be problem with anything you may plant. Al

The hedge provided both privacy and also hid some ugly looking powerlines.

We are now thinking of taking down the lemonwood hedge as well and just starting with a clean slate. The lemonwoods are probably 30 years old and look terrible!

Maybe I should post some pics?

I would like to hide most of the powerlines, but I am not overly fond of strict perimeter plantings like hedges.
So key groups of smaller trees (ht: 30" by width: 20ft max) or large taller shrubs that can be grouped together might work.

The main problem is that most of the backyard is concreted...then there's a pool. So I have to be careful of what I plant.

The depth of the garden strip around the property is about 14 feet, but the neighbours don't seem to care too much if branches goes on their side. The pool is an additional 6 feet away from the garden strip due to a concrete walk around it.

The bamboo would solve alot of problems (in a timely fashion) in the one corner where there is an ugly hydro pole...I just wasn't sure if it would look out of place or not.

Designing is confusing!

Pics would help very much.

I think the bamboo would look good, but it is messy.
It does well in full sun, I believe.

Bamboo only looks right in an Asian theme garden. It is very invasive also, once you plant it, you may never be able to get rid of it.

I'd second the advice that bamboos can look very nice in a Mediterranean style garden, but are seriously messy year round with constant leaf drop, and most do appreciate regular summer irrigation to look their best. If your pool has an automatic pool cover, the Alphonse Karr may be worth doing, with Mexican Weeping Bamboo another beautiful candidate that is also a clumper. I'd suggest you research large shrub/small tree choices via the Sunset Western Garden Book sections on Trees, Hedges, Drought tolerant plants, Plants near pools amongst others. There are real advantages to using trees that don't continuously drop leaves/flowers around an open pool. Ceanothus Ray Hartman is also messy in bloom season. Tried and true "cleaner" trees would include Tristaniopsis laurina, Eriobotrya deflexa, Podocarpus latifolius or P. gracilior, to name a few.

Other main issues to sort out regarding major plantings is whether you will be irrigating or not. As Al also mentioned, make sure you've got the Ivy under control or don't ignore regrowth from seed or creeping in from the neighbors. Posting pictures would definitely help with getting advice, and you might really benefit from hiring a landscape designer to help you sort out the design issues and narrow down the plant choices/decisions.